Rubella in South-East Asia, 2013–2021: Vaccine Coverage Rose From 12% to 86%

Rubella is the leading cause of vaccine-preventable birth defects. Infection during pregnancy, especially in the first trimester, can cause miscarriage, fetal death or congenital rubella syndrome (CRS) — malformations that often include vision, hearing or heart defects. CRS kills infants and children and shortens adults' lives.

In 2013, the 11 countries of the World Health Organization's South-East Asia Region (SEAR) — Bangladesh, Bhutan, Burma (Myanmar), India, Indonesia, Maldives, Nepal, North Korea, Sri Lanka, Thailand and Timor-Leste — adopted goals of measles elimination and rubella and CRS control by 2020. In 2019 they widened this to eliminating both measles and rubella by 2023.

Measles and rubella work go together: rubella-containing vaccine (RCV) is given as a combined measles-rubella shot, and rubella is found through measles or fever-and-rash surveillance.

Key findings

• Before 2013, only five countries used RCV. Six more introduced it during 2013–2021, so all 11 now use it routinely.
• Coverage with the first dose (RCV1) rose by more than 600%, from 12% in 2013 to 86% in 2021.
• About 515 million people were vaccinated in supplementary campaigns.
• Reported rubella cases fell 80%, from 10,434 to 2,103, and incidence from 5.5 to 1.1 cases per million.
• Maldives and Sri Lanka were verified as having eliminated rubella in 2020. Bhutan, North Korea and Timor-Leste had stopped endemic transmission for more than 36 months and were still awaiting verification in May 2023.

Country by country

Reported rubella cases and first-dose vaccine coverage, South-East Asia Region, 2013–2021. Source: WHO and UNICEF data, from CDC's MMWR.

Surveillance

• By 2021 every country ran case-based measles and rubella surveillance with lab confirmation; a suspected case everywhere was "acute fever with maculopapular rash."
• The regional laboratory network, set up by 2003, had grown by 2021 to 58 proficient labs plus a regional reference lab in Thailand, with at least one in every country.
• Sensitivity is measured by "discarded" cases — suspected cases shown to be neither measles nor rubella. The target is two or more per 100,000 people a year. The regional rate rose from 0.91 to 1.52, but only five countries met the target in 2021 (two in 2013):

• All countries have CRS surveillance: North Korea, Sri Lanka and Thailand through national disease reporting, the other eight through sentinel sites. Reported CRS cases rose from 23 to 401, most likely because surveillance improved, not because more pregnant women caught rubella.
• Genotypes found: 2B in India and Thailand, endemic 1E in Thailand and 1J in India — though too few specimens were tested to say much about transmission.

Verification

A Regional Verification Commission was set up in 2016 and updated its framework in 2020. All 11 countries have national verification committees that report to it every year.

Setbacks

• During the COVID-19 pandemic, regional RCV1 coverage fell from 93% in 2019 to 86% in 2021.
• Of an estimated 25 million infants worldwide who missed RCV1 in 2021, about 18% lived in the region, including 2.4 million in India and 1.2 million in Indonesia.
• Surveillance suffered too, likely because distancing and masking cut transmission of rubella and other viruses, national movement restrictions cut clinic visits for fever and rash, and surveillance staff were moved to pandemic work.
• An independent review found immunity gaps, weak surveillance, poor outbreak response, funding gaps and pandemic damage all threatened the 2023 target.

Limits: coverage comes from administrative data that may miscount doses or target populations; not every infection causes fever, gets care or gets reported; not all countries consistently report CRS; and genotype data are few and unrepresentative.

What's needed

The authors call for:

1. the highest national commitment and partner support;
2. at least 95% coverage with RCV1 through routine immunization;
3. high-quality vaccination campaigns;
4. more sensitive surveillance and more specimens for virus detection and genotyping;
5. using elimination work to restore routine immunization and close gaps for all vaccine-preventable diseases.

The region's births are 24% of the world's infants who survive past their first birthday, so progress here matters for rubella worldwide.

Sources

Based on Khanal S, Bahl S, Sangal L, et al., "Progress Toward Rubella Elimination — World Health Organization South-East Asia Region, 2013–2021," Morbidity and Mortality Weekly Report 72(25), CDC; a work of the United States government in the public domain.